var obj = {
    name: 'along',
    age: 32
}
for (var k in obj) {
    console.log(k, obj[k]);
}

var a = Object.keys(obj) //[ 'name', 'age' ]

Object.keys(obj).forEach(function (element) {
    console.log(element, obj[element]);
})


var arr = ['xiaoming', 'xiaohong', 'xiaoli',]

for(var k in arr){
    console.log(k,arr[k]);
}
console.log('-------------------------');
var arr1 = Object.keys(arr) //[ '0', '1', '2' ]
Object.keys(arr).forEach(function (element) {
    console.log(element, arr[element]);
})

Array.prototype.push = function () {
    console.log('在数组上修改push方法');
}
arr.push()




